Adhesive coated label with a silicone resin release coating applied thereto

ABSTRACT

AN ADHESIVE COATED LABEL INCLUDES A COATED PAPER CONSTRUCTION HAVING A PAPER BASE PRINTED WITH LABEL&#39;&#39;S MESSAGE ON ONE SIDE AND COATED ON THE OTHER SIDE WITH AN ADHESIVE. A RELEASE COATING ON THE PRINTED SURFACE PREVENTS STICKING OF THE ADHESIVE TO THE PRINTED SIDE OF THE LABEL AND ALLOWS FOR GATHERING THE LABEL STOCK INTO ROLLS FOR CONVEN-   IENT USE. THE METHOD BY WHICH THE LABEL IS MADE INCLUDES PRINTING THE LABEL, APPLYING A RELEASE AGENT IN COATED FORM. CURING THE RELEASE AGENT AND THEREAFTER APPLYING AN ADHESIVE COATING TO THE UNDERSIDE OF THE LABEL.

Arii 26, HQ?! .FUNK ETAL M. ADHESIVE COATED BEL WITH A L RELEASE COATINGAPPLIE TH T0 Filed April 18. 1968 United States Patent O US. Cl. 161-1671 Claim ABSTRACT OF THE DISCLOSURE An adhesive coated label includes acoated paper construction having a paper base printed with labelsmessage on one side and coated on the other side with an adhesive. Arelease coating on the printed surface prevents sticking of the adhesiveto the printed side of the label and allows for gathering the labelstock into rolls for convenient use. The method by which the label ismade includes printing the label, applying a release agent in coatedform, curing the release agent and thereafter applying an adhesivecoating to the underside of the label.

BACKGROUND OF THE INVENTION Adhesive coated labels have been used forvarious purposes including the marking of price data on such packages asbread bags. For convenience in use these labels are gathered in rollform. Heretofore rolls of labels have required the use of aninterleaving sheet to prevent the adhesive side of the label fromsticking to the printed side. While this arrangement possesses certainadvantages, it is nevertheless necessary to dispose of the interleavedsheet after using the labels. Moreover, the interleaved sheet adds tothe cost of the overall label stock without the customer deriving acommensurate benefit from such added cost.

SUMMARY OF THE INVENTION The present invention contributes to the art ofadhesive coated labels and provides a label which eliminates the needfor interleaved sheets which prevent sticking of the adhesive side ofthe label to the printed side when the labels are in roll form.

In one embodiment of the present invention, a pressure sensitive labelincludes a base sheet of label stock printed with the usual message. Theprinted surface is overcoated with a layer of nitrocellulose lacquer andthereafter, such lacquer coating is covered with a coating of a releaseagent. The release agent preferably is a thermosetting silicone resinwhich provides for release and easy unwinding of the labels from rollform. Prior efforts to use silicone as a release agent have not beensuccessful because the silicone transfers to and reduces theeffectiveness of the adhesive side of the label when the labels are inroll form. The silicone acts as a release agent for the adhesive sidewith the undesirable consequence of preventing the label from stickingas intended to package or other product.

OBJECTS OF THE INVENTION Accordingly, it is the object of the presentinvention to provide a new and improved adhesive coated label and a newmethod of making the label.

Another object of the present invention is to provide a pressuresensitive label which eliminates the need for an interleaved sheet.

Another object of the present invention is to provide a pressuresensitive label having a release coating on the printed side thereofwhich does not transfer to the adhesive side of the label when thelabels are in roll form.

3,575,788 Patented Apr. 20, 1971 "Ice Another object of the presentinvention is to provide a pressure sensitive label which may readily behandled by label applicating machines.

Other and further objects of the present invention will occur to oneskilled in the art upon and understanding of the following illustrativeembodiment of the invention, or upon the employment of the invention inpractice.

DESCRIPTION OF THE DRAWINGS A preferred embodiment of the invention hasbeen chosen for purposes of illustration and description and is shown inthe accompanying drawings forming part of the specification wherein:

FIG. 1 is an enlarged section view of a label according to the presentinvention;

FIGS. 2 and 3 represent packages illustrating the manner in which thelabel according to the present invention may be used;

FIGS. 4 and 5 illustrate the method for making the label according tothe present invention.

Referring more particularly to FIG. 1, the label 1 includes a base layer2 of the usual paper stock which is printed at 3 with a suitable link toprovide a message on the label. Preferably, the paper stock isapproximately 40 to 60 lbs, per ream with the usual clay coating to makethe paper receptive to the printed data on one side and t0 the adhesiveon the other side.

The paper layer 2 is printed with a high heat resistant nitrocellulosebase ink having a plasticizer content selected so as not to inhibitcuring. The label is next overcoated with a layer 4 of high heatresistant nitrocellulose lacquer which prevents an unfavorableinteraction between the release coating and the clay coated paper. Thatis to say the nitrocellulose lacquer acts as a barrier to prevent anouter release agent layer from contacting the clay coating. Such contactwould inhibit the curing of the release agent.

Preferably, the paper layer is printed with the ink and the lacquerovercoating by using flexographic printing techniques.

As shown in FIG. 1, a release coating 5 is applied to the lacqueroverlayer. The release coating prevents an adhesive layer 6 fromsticking to the surface of the printed layer. The release coating ispreferably a thermosetting silicone resin and is applied over thenitrocellulose lacquer coating 4. A suitable thermosetting siliconeresin is a silicone rubber polymer (as for example Dow Cornings Syl-oif23) dissolved in a suitable solvent like xylene or toluene to about 7 to15% solids. In addition, an organic metallic catalyst (for example DowCornings Co Catalysts 23A, XY 139, or XY dissolved in a suitable solventlike toluene may be used as a catalyst in curing the thermosettingsilicone resin.

The silicone resin coating is applied in a suitable manner as forexample by a gravure cylinder 7 (FIG. 4) and is preferably applied inthe amount of one-half pound of coating per ream of paper stock. Aftercoating, the release coating is cured in an oven 8 at a temperaturebetween 350 F. and 500 F. for about 4 to 6 seconds.

After curing, an adhesive coating 6 is applied to the underside of thepaper layer. The adhesive coating is preferably pressure sensitive.

A suitable pressure sensitive adhesive may be produced by combiningingredients generally identified as a film former, a tackifying resin(or a combination of tackifying resins) and a plasticizer.

Preferably the film former belongs to the class of ethylene vinylacetate copolymers. Such copolymers having an acetate content of from14% to 40% and melt indices from 2.4 to 350 have been used in thepresent invention.

As to tackifying resins, either a single resin or a combination ofresins may be used. If a single resin is used one liquid at roomtemperature is preferred. The tackifying resins are chosen from rosinderivations, terpenes, phenolic resins or hydrocarbon resins. Preferablythe preferred tackifying resin includes a composition mixing astaybelite resin and a triethylene glycol ester of hydrogenated rosin.

Difierent plasticisers may be used in making the pressure sensitiveformulation, including dibutyl tartrate, glycerol monoricinoleate,mineral oils, Santicizer HB-40, Plastolein 971 (polyester type),tricresyl phosphate, dibutyl phthalate, and Santicizer 8 (N-ethyl oandptoluene sulfoamide).

Various changes have been made in the formula for the pressure sensitiveadhesive and such changes have been examined in respect to the adhesivecharacteristics of the resultant product. The film former was variedfrom about 15% of the composition to 60% and the other ingredients werevaried in relation to the film former. The plasticizer was varied fromto 40% and the tackifying resin from to 70%. Adhesiveness resulted inthese ranges.

FIGS. 4 and 5 illustrate the preferred method for making labelsaccording to the present invention. As shown in FIG. 4, the paper layer2 has been printed with a message and has been overprinted with thenitrocellulose lacquer coating 4. Next the layer 5 of thermosettingsilicone resin is applied by means of a gravure cylinder 7 over thesurface of the lacquer coating. Thereafter, the label web 1 is passedthrough a dryer 8 Where the silicone resin release coating is cured at atemperature of between 350 and 500 F. for about 5 seconds. After suchcuring the label Web 1 is coated on its other side with the pressuresensitive adhesive 6 which in cooperation with a smoother bar 9 providesa uniform tackiness over the surface of the web. A suitable roller 10and glue supply 1 may be used to apply the adhesive coating. If desired,the label web may pass through a pan of cooling rollers 12 after theadhesive coating is applied.

In a final step, the web may be slit into individual Widths of labelstock for shipment to a customer. FIGS. 2 and 3 illustrate packages 14,15 which are using the label .as an end label 16 or as a price sticker17 affixcd to the package (as in FIG. 4). In FIG. 5, the label stock may4 be used as a header 18 aifixed in the nature of a fin or a header tothe mouth of a plastic (usually polyethylene) bread bag.

It will be seen that applicant has provided a new pressure sensitiveadhesive label, The advantages of thi new label are that it eliminatesthe need for an interleaved sheet and new label may readily be handledon label applicating equipment.

Various changes may be made to the form, constru tion, arrangement andcomposition without departing from the spirit and scope of the inventionand without sacrificing its advantages and it is to be understood thatthe embodiments set forth are to be interpreted as illustrati've and notin a limiting sense.

What is claimed is:

1. A label comprising a clay coated paper sheet having a first surfaceand a second, opposite surface, the first surface being printed with anitrocellulose base ink and overcoated with a nitrocellulose baselacquer, a heat-cured thermosetting silicone resin release coatingapplied over the nitrocellulose lacquer overcoating, the second surfacebeing coated with a pressure-sensitive adhesive.

References Cited UNITED STATES PATENTS 2,133,914 10/1938 Burke 161406X2,578,150 12/1951 Rathke l6l167X 2,588,367 3/1952 Dennett 117-122PS2,768,460 10/1956 Northrup 16l167UX 2,860,083 11/1958 Nitzsche et a1.117122PS 2,934,467 4/1960 Bergstein 161209 3,111,449 11/1963 Gold et a1.16l406X 3,263,677 2/1966 Bradstreet 161-167X 3,328,482 6/1967 Northrupet al. 161406X 3,394,799 7/1968 Ritson et al 16l406X 3,432,333 3/1969Hurst 161406X JOHN T. GOOLKASIAN, Primary :Examiner G. W. MOXON II,Assistant Examiner US. Cl. X.R.

